1. Field of the Invention
The present invention relates to color filters, and especially to color filters used in display devices such as liquid crystal display devices.
2. Description of the Prior Art
Liquid crystal display devices have become very popular in recent years because of their advantages over display devices that utilize cathode ray tubes. In particular, liquid crystal display devices are thinner, and offer lower power consumption.
Liquid crystal display devices are generally divided into three types according to the way in which they utilize available light: transmissive type, reflective type, and transflective type.
A transflective liquid crystal display device has the functions of both a transmissive and a reflective liquid crystal display device, and has received much attention lately. The transflective liquid crystal display device reflects ambient light when it is used in a bright ambient environment, and at this time the transflective liquid crystal display device does not need to use its backlight. Thus, the transflective liquid crystal display device has lower power consumption than a transmissive liquid crystal display device. On the other hand, when the intensity of light in the ambient environment is low, the transflective liquid crystal display device can use light beams both from the backlight and from the ambient environment. Therefore, at this time the transflective liquid crystal display device exhibits a higher light intensity than a reflective liquid crystal display device.
Referring to FIG. 11, a color filter 1 applied in a transflective display device of the prior art is shown. The color filter 1 comprises a multiplicity of pixels 10 arranged in a regular, rectangular array of rows and columns. Each pixel 10 comprises three sub-pixels 10A, 10B, 10C of Red, Green and Blue pigment respectively, the sub-pixels 10A, 10B, 10C being arranged in a row. Each sub-pixel 10A, 10B, 10C comprises a transmission sub-section 102, and a reflection sub-section 101 above the transmission sub-section 102.
FIG. 12 shows a display effect of the transflective liquid crystal display operating in a transmission/reflection mode. Whether the transflective liquid crystal display is used in a bright environment or in a low light intensity environment, the color filter 1 causes the transflective display device to exhibit hue diversity. This reduces the quality of the displayed image.
Further, in operation, the light beams from the ambient environment sequentially pass through the reflection sections 101 twice, and the light beams from the backlight pass through the transmission sections 102 only once. The optical paths of the light beams passing through the reflection sections 101 are twice as long as the optical paths of the light beams passing through the transmission sections 102. This causes the transflective display device to exhibit hue diversity. That is, the light intensity, contrast and saturation are not uniform. This further reduces the quality of the displayed image.
Therefore, it is desired to provide a color filter and a display device using the same which overcome the above-described disadvantages of the prior art.